Israeli Prime Minister Benjamin Netanyahu on Wednesday thanked Barack Obama for standing up for Israel's right to defend its existence, at a welcome ceremony after the US president landed near Tel Aviv.

"Thank you for defending Israel's right to unequivocably defend its right to exist," he said at Ben Gurion airport, shortly after Obama arrived for his first trip to Israel since becoming president more than four years ago.

President Barack Obama said on Wednesday that "peace must come to the Holy Land," insisting the United States was proud to stand as Israel's strongest friend and ally, after landing in Tel Aviv.

Peace must come to the Holy Land. We will never lose sight of an Israel at peace with its neighbours," Obama said, as he began his first visit to the Jewish state as president. "Our alliance is eternal. It is for ever."

Barack Obama landed in Israel today for the first time as US president, on a mission to ease past tensions with his hosts but facing scepticism about his plans to thwart Iran's nuclear threat.

Air Force One landed at Ben Gurion airport near Tel Aviv to kick off a three-day trip on which Obama will meet Israeli leaders and make a short visit to the West Bank, before heading to Jordan to consult with King Abdullah II.

The plane rolled to a stop to the peal of trumpets from a military band and Obama smiled broadly as he embraced Israeli Prime Minister Benjamin Netanyahu and then President Shimon Peres, saying: "How are you, my friend?" They then stood to attention for the US and Israeli national anthems.

Obama's long-awaited visit, the debut overseas trip of his second term, may be marked more by symbolism than serious diplomatic substance and will expose diminished US ambitions of forging peace between Israelis and Palestinians.

The president says he is carrying no new peace plans and instead plans to listen to the new Israeli government and Palestinians disaffected with his approach, leading some experts to question why he is coming at all.

He must also navigate the treacherous regional politics of the Middle East, amid new scrutiny over his wariness of deeper US involvement in Syria as government forces and rebels accuse one another of using chemical arms.

Obama will come face-to-face with Israel's security challenge at the airport by viewing a mobile battery of Israel's US-funded Iron Dome anti-missile system.

Then he will head to Jerusalem for talks with Peres before sitting down with Netanyahu, with whom he has had a prickly relationship.

During his visit, Obama will pointedly court the historic symbolism of the Jewish State when he inspects the Dead Sea Scrolls and visits the tomb of Theodor Herzl, founder of modern Zionism.

The choreography is intended to show Israelis, Arabs and political foes back home that Obama is deeply committed to Israel's security and future, despite some scepticism about his motives.

He is on tricky political ground: a survey by the independent Israel Democracy Institute showed that while 51 percent of the Jewish Israeli respondents considered Obama neutral in his attitude toward Israel, 53.5 percent did not trust him over Israel's vital interests.

So, mounting a charm offensive, Obama will deliver a speech to hundreds of young Israelis on Thursday.

Obama and Netanyahu will have to smooth over an often difficult personal chemistry following previous spats, but the visit is unlikely to narrow differences over how soon Iran will have a nuclear weapons capability.

Obama told Israeli television that Iran would not be able to build a nuclear weapon for "over a year or so." Netanyahu warned last year that Iran would have the capacity to produce a bomb much earlier, within months from the current date, and questions whether sanctions will change Tehran's calculations.

The difference in "red lines" on Iran may reflect each side's differing capacities to launch meaningful action against Iran -- but Obama will likely caution Netanyahu against an early Israeli strike.

While he will not bring a specific Middle East peace proposal, officials insist Obama's commitment to a two-state solution for Israel and the Palestinians is undimmed.

Washington, pushed by new Secretary of State John Kerry, would revive the Arab peace plan of 2002.

The plan holds out the carrot of recognition for Israel from key Arab states in return for a Palestinian state and a withdrawal from the occupied territories, but has been deemed unworkable by Israelis.

Palestinian president Mahmud Abbas hopes Obama will help broker the release of more than 1,000 Palestinian prisoners from Israeli jails and wants $700 million in blocked US aid freed up.

Obama will tell the Palestinians that initiatives like seeking statehood recognition at the UN are counterproductive, while warning Israel that settlement building undercuts the chances of resuming peace talks.

But Palestinians want Obama to show more muscle in attempting to get peace talks restarted, warning that the settlement row that thwarted the last US initiative threatened the entire idea of Palestinian statehood.

"We don't have time," he said. "Either the settlements are stopped immediately... or you can kiss the two-state solution goodbye." In Israel and Jordan, Obama will experience oases of relative calm in a region rocked by unrest spawned by the Arab Spring uprisings.

His refusal to provide arms or ammunition to disparate rebel groups battling forces loyal to Syria's president Bashar al-Assad, fearing they could be funnelled to extremists, will come in for particular scrutiny.